1、Designation: E2396/E2396M 15Standard Test Method forSaturated Water Permeability of Granular Drainage MediaFalling-Head Method for Vegetative (Green) Roof Systems1This standard is issued under the fixed designation E2396/E2396M; the number immediately following the designation indicates the yearof o
2、riginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers a procedure for determining thewater
3、 permeability of coarse granular materials used in thedrainage layers of vegetative (green) roof systems.1.2 This test method addresses water permeability under thelow-head conditions that typify horizontal flow in vegetative(green) roof applications.1.3 This test method is suitable for coarse-grain
4、ed materialswith 100 % of the material retained on the U.S. #8 2.25 mmsieve. It is not suitable for finer-grained materials.1.4 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore,
5、eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to e
6、stablish appro-priate safety and health practices and to determine theapplicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C29/C29M Test Method for Bulk Density (“Unit Weight”)and Voids in AggregateC130 Specification for Lightweight Aggregates for Concrete(
7、Withdrawn 1954)3E631 Terminology of Building ConstructionsE2114 Terminology for Sustainability Relative to the Perfor-mance of Buildings3. Terminology3.1 Definitions:3.1.1 For terms related to building construction, refer toTerminology E631.3.1.2 For terms related to sustainability relative to thepe
8、rformance of buildings, refer to Terminology E2114.3.2 Definitions of Terms Specific to This Standard:3.2.1 water permeabilitythe coefficient which when mul-tiplied by the hydraulic gradient will yield the apparentvelocity with which water (at 68F) will move through across-section of media.3.2.2 wet
9、 densitythe density of coarse granular drainagecourse materials determined after immersion for 24 hours.4. Summary of Test Method4.1 This procedure involves measuring the water permeabil-ity of coarse granular materials under the low-head conditionsthat characterize the environment in vegetative (gr
10、een) roofsystems. A falling-head technique is used. Incidental to theprocedure is the measurement of the wet density of themedium.5. Significance and Use5.1 This test method addresses performance characteristicsfor vegetative (green) roof systems with respect to the waterpermeability of the drainage
11、 media.5.1.1 Water permeability of coarse materials is highly influ-enced by the head conditions under which it is measured. Invegetative (green) roofs, coarse materials are frequently usedto create drainage zones for percolated rainfall.5.1.2 This test method is intended to provide water perme-abil
12、ity data that is relevant to this design condition that ischaracterized by horizontal flow under low-head. This will alsoallow the performance of granular drainage layers in vegetative(green) roof systems to be compared directly to alternativecomponents, such as geocomposite drain layers.5.2 Determi
13、ning the performance characteristics of vegeta-tive (green) roof systems provides information to facilitate theassessment of related engineering aspects of the facility. Such1This test method is under the jurisdiction of ASTM Committee D08 on Roofingand Waterproofing and is the direct responsibility
14、 of Subcommittee D08.24 onSustainability.Current edition approved June 1, 2015. Published July 2015. Originally approvedin 2005. Last previous edition approved in 2011 as E2396 11. DOI: 10.1520/E2396_E2396M-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Custo
15、mer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, W
16、est Conshohocken, PA 19428-2959. United States1aspects may include structural design requirements, mechani-cal engineering and thermal design requirements, and fire andlife safety requirements.5.3 Determining the performance characteristics of vegeta-tive (green) roof systems provides information to
17、 facilitateassessment of the performance of one vegetative (green) roofsystem relative to another.6. Apparatus6.1 The apparatus consists of nested cylinders constructedfrom stainless steel or plastic:6.1.1 Inner cylinderinner diameter of 3.75 in. 9.53 cm,32 in. 81.3 cm long as shown in Fig. 1. Perfo
18、rated at thebottom (50 % open area), with marks at 6 and 8 in. 15.2 and20.3 cm below the top of the cylinder,6.1.2 Outer cylinderinner diameter of 5.75 in. 14.6 cmas shown in Fig. 1. This cylinder must be watertight,6.1.3 U.S. #8 2.25 mm sieve disc, 3.55-in. 9.02-cmdiameter, and6.1.4 Scale with accu
19、racy of 0.005 oz 0.14 g.6.2 The apparatus is mounted so that the 8-in. 15.2-cmmark of the inner cylinder is level with the top of the outercylinder.7. Conditioning7.1 Before conducting the tests, with the sieve in place, fillthe apparatus with water and determine the elapsed time inseconds that it t
20、akes for the water level to fall 6 in. 15.2 cmto the first mark. This value will be used to establish the upperlimit on the measurement of water permeability using theapparatus.8. Procedure8.1 Place the sieve disc into the inner cylinder. Fill with thegranular material. Take care to prevent segregat
21、ion of finerparticles within the column. Shake or vibrate the materialvigorously to compact it into the cylinder. Fill to the 8-in.20.3-cm mark. If the specific gravity of the particles is lessthan 1.0, place a sieve disc on top of the sample and weighdown with glass marbles.8.2 Begin introducing wa
22、ter into the inner cylinder. Thewater will fill the inner and outer cylinders and begin tooverflow. Continue to introduce water for 30 min. Asnecessary, add more media to maintain the level of the mediaat the 8-in. 20.3-cm mark. The temperature of the watershould be 68 6 5F 20 6 2.75C. Check the tem
23、perature byplacing a thermometer in the annular space between the twocylinders.8.3 Stop introducing water to the inner cylinder and note theelapsed time, in seconds, for the water level to descend to the6-in. 15.2-cm mark on the inner cylinder. Repeat three timesand average the results.8.4 Allow the
24、 material to stand overnight in the cylinder.8.5 Weigh a graduated beaker.8.6 After 24 hours, drain the cylinder.8.7 After 15 min have elapsed, measure a portion of thegranular medium into the graduated beaker. Weigh the beakerwith its contents and subtract the weight of the beaker. Usingthe measure
25、d volume of the granular medium in the beaker,compute the wet density of the medium in units of lb/ft3kg m3.FIG. 1 Equipment Fabrication DetailE2396/E2396M 1528.8 Conduct all tests in duplicate. If the results of two testsdiffer by more than 5 %, then repeat.9. Calculation of Results9.1 Compute the
26、upper limit of the apparatus for determin-ing water permeability as follows:Kl5 0.5*1996/t (1)Kl= method limit for measuring water permeability in./min, andt = elapsed time measured when the apparatus containsonly water s.9.2 Compute the water permeability, as follows:Kf5 1996/T in. 2 lb! (2)Kf5 84.
27、50/T!SI!Kf = water permeability, in/min cm/sT = Elapsed time, sIf Kf Kl, then report Kf Kl10. Report10.1 The report shall contain the following information:10.1.1 Sample designation,10.1.2 Grain-size distribution of the medium (SpecificationC130),10.1.3 Dry density of the medium (Test Method C29/C29
28、M),10.1.4 Wet density of the medium,10.1.5 Water permeability,10.1.6 Upper limit of the method for measuring waterpermeability, and10.1.7 Temperature of water in the outer cylinder.11. Precision and Bias11.1 PrecisionThe precision of the procedure for measur-ing water permeability is being determine
29、d. Parties interestedin participating in interlaboratory test programs should contactCommittee E60.11.2 BiasThe bias for these measurements is undeter-mined because there are no reference values available for thematerials used.12. Keywords12.1 granular, coarse aggregate; low-head; vegetative(green)
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